In a successive approximation type ADC (Analog to Digital Converter), a reference voltage is input to a DAC (Digital to Analog Converter) and the set voltage of the DAC is compared with an input voltage, and by controlling the DAC so that the voltages get closest to each other, the input voltage is converted into a digital code. As the DAC system, a capacitor DAC, a resistor DAC, and the like are given.
In such a successive approximation type ADC, if the regeneration time of a comparator which compares the set voltage and the input voltage is long, a large conversion error might be caused. The regeneration time is time it takes for the output value of the comparator to stabilize from a metastable state (pre-stable state) to a stable state).